A characteristic reaction of the compounds with the general formula CnH2n is

Compounds with the general formula CnH2n undergo a characteristic reaction called polymerization. This is a chemical process where small molecules, called monomers, react with each other to form larger molecules called polymers. In this reaction, the double bond between the two carbon atoms in the CnH2n molecule opens up and links with the double bond in another molecule of CnH2n, creating a long chain of repeating units. This reaction is commonly seen in the synthesis of plastics and other polymers.